Electrostatic attraction-driven assembly of non-noble metallo-supramolecular polymers with single-walled carbon nanotubes for boosting photocatalytic hydrogen evolution

Abstract

The search for photoactive materials that are able to efficiently produce solar fuels is a growing research field to tackle the current energy crisis. Herein, we have prepared two ionic non-noble metallo-supramolecular polymers Se-MTpy (M = Co or Ni), and constructed their composites with single-walled carbon nanotubes (CNTs) via electrostatic attraction and π–π interactions for efficient and stable photocatalytic hydrogen evolution. In the photocatalytic system, the cationic Se-MTpy as host and anionic CNTs as guest are assembled into a binary composite, which exhibits superior photocatalytic activity under visible light irradiation (> 420 nm). The optimized CNT@Se-CoTpy composite, containing 1.2 wt% metal loading, achieves 7 times higher hydrogen evolution rate (2.47 mmol g−1 h−1) than bare Se-CoTpy (0.35 mmol g−1 h−1). This is attributed to the constructive formation of junctions between polymer and CNTs, facilitating interfacial charge transfer and transport for efficient proton reduction. The composite system also shows high photostability after continuous irradiation for ~30 h. The combination of experimental and theoretical analysis demonstrates the higher activity for reducing H2O to H2 of Se-CoTpy than Se-NiTpy. The feasible interfacial architecture proposed in this study represents an effective approach to achieve high photocatalytic performance. Graphical abstract: [Figure not available: see fulltext.]